Zones 5a and 5b are two of the coldest in the country. This condition makes it difficult for plants to adapt, grow, and develop. Fortunately, some plants can thrive in this environment. Let’s get to know them!
The environmental conditions in zones 5a and 5b can support the growth of sedum, hostas, catmint, bee balm, and Russian sage. However, yarrow, hydrangea, and coneflowers only grow best in zone 5b. The minimum average temperature of the two zones is different: -15–20°F for zone 5a and -10–15°F for zone 5b.
But other than the minimum average temperature, what are the other differences between the two subzones? Are they different in terms of rainfall? Soil conditions? Read forward to find out!
Stonecrop or sedum can tolerate temperatures as cold as -30°F, so they can be grown in zones 5a and 5b. It grows in various sizes, from 3 inches to 3 feet. It is a perennial plant with star-shaped red, white, or yellow flowers. It has a fleshy stem and succulent leaves.
Let me start this article by defining a perennial plant, since they are in this list Perennial plants are those plants that can live from year to year. Examples are trees and most of the flowering plants on our list.
How should you care for sedum? To grow sedum to its best, we should consider different environmental factors such as temperature, lighting, soil, and watering.
For lighting conditions, sedum prefers 5 hours (or more) of either full sun or partly shaded conditions. However, in maintaining these lighting conditions, you should also make sure that your soil will not dry out! This is because very dry soil is not optimal for sedum growth.
With this, you should water your sedum plants weekly, especially if your soil has a high drainage capacity and is porous.
You can tell that your soil has high drainage capacity if it dries out easily, even without sunlight or any sources of heat.
Also, hummingbirds are one of the common pollinators of sedum. Grow this in your garden if you want to see these colorful birds flying around among the plants!
Hostas can grow in cold temperatures down to -40°F, so they can be planted in zones 5a and 5b. They are perennials that have pointed, oval, heart-shaped, or circular broad leaves. They have distinct waxy, bright green foliage and lavender, lilac, and pink flowers. Hostas can grow up to 3 feet tall.
A key characteristic of hostas is their low-maintenance nature. However, you should still take note of the different key factors to ensure the proper growth of your hostas.
Hostas plants can grow even with partial shade or shady conditions. They can survive even with just 2 hours of sunlight exposure.
Frequent fertilization of the soil is not required in growing hostas, since they only need light fertilization.
You can use slow-release fertilizers or 0.5 pounds of 10-10-10 like the one below
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You may also opt to use mulch to retain water in your hostas. It is important to keep them moist, but not too wet since they only require a medium amount of watering.
Catmint, also known as nepeta, can survive in temperatures as low as -30°F so it can be grown in zones 5a and 5b. It has a strong aroma and produces long-blooming purple, blue, or white flowers. The leaves of catmint are soft, oval, and silvery green. Catmint plants can grow up to 3 feet tall and are perennial.
Many gardeners claim that growing catmint is simple. I would say this is true to some degree.
You must, however, be able to maintain 6 hours of full sunlight and use soil with good drainage. Catmint is drought-tolerant and can grow in a variety of soil types, including clay, sandy loam, and shallow rocky soil!
They must be watered every other day, starting from germination up to the point where they grow to full plant. After that, you can gradually shift to watering only once a week.
As its name suggests, this plant has a strong minty odor which makes them very attractive to cats.
Even in cold temperatures of -20°F, bee balm can thrive. Therefore, they can grow in zones 5a and 5b. It is a perennial plant and has white, pink, red, purple, and lavender flowers. This plant’s leaves are usually blue-green, its stems are square and red, and it can grow up to 4 feet tall.
Bee balm is known by many other names such as horsemint, bergamot, monarda plant, and Oswego tea.
During dry periods, water your bee balm plants every 7 to 10 days for better growth. Bee balms thrive in moist, well-drained soils that receive 6 hours of full sun.
In terms of the lighting conditions, your garden should receive at least 6 hours of direct sunlight.
Otherwise, bee balms growing in partial shade will not produce a sufficient number of flowers. They also become more susceptible to plant diseases such as powdery mildew.
Russian sage can withstand temperatures as low as -20°F, so it can grow in zones 5a and 5b. Its leaves are long and gray-green, while its stems are square and silvery-gray. It has small, aromatic, violet flowers that bloom during the summer. This bushy plant can grow from 3 to 5 feet tall and tolerate drought.
Russian sage is another perennial member of the mint family.
For lighting, the Russian sage requires at least 6 hours of direct sunlight. Furthermore, the soil must be aerated and well-drained.
More importantly, though, it is best not to overwater your russian sage because this can cause rotting of the roots and plant parts.
It is recommended to only water the russian sage plants on a regular basis while they are still developing, until roots form. Following that, you can water your russian sage once a week.
Grow yarrow in zone 5b with temperatures as low as -13°F. This herbaceous perennial has tall stems, fern-shaped green to grayish-green leaves, and small red, pink, yellow, or white flower heads. Yarrow plants can grow from 2 to 4 feet tall.
Yarrow requires at least 6 hours of full sun exposure.
Overall, though, they are a low-maintenance crop, which is an excellent plant characteristic that every gardener desires!
Surprisingly, it has a very low water requirement. You should only water it once a month.
In terms of soil requirements, they prefer well-drained, acidic to slightly alkaline soils.
Hydrangea can survive in cool temperatures of -12°F, so they can thrive in zone 5b. They are perennial shrubs that grow pink, blue, white, or purple umbrella-shaped flowers at the terminal end of stems. Their leaves are oval and green. Hydrangeas can stand from 2 to 6 feet tall.
Here is an interesting trivia about hydrangeas: The flower color of hydrangeas is a reflection of soil pH.
If hydrangea plants bloom blue, your soil is acidic (<5 pH), while if they bloom pink, your soil is alkaline (>6.5 pH). Purple flowers are most likely to grow in soil that is between acidic and alkaline.
Hydrangea plants can grow in areas with full sunlight, partial shade, or full shade. Most hydrangea varieties grow best with at least 6 hours of direct sunlight.
Their soil must be well-drained and rich in nutrients! However, do not resort to using animal manure since it is high in nitrogen, which may be bad for your hydrangeas. They could experience nitrogen toxicity and die!
You can use the same slow-release fertilizer and 10-10-10 fertilizer that I recommended above for hydrangeas!
Watering in hydrangeas is critical since it must be balanced—do not underwater or overwater! It is recommended to water hydrangeas 2 to 3 times a week. You can also add mulch to retain water in the soil for as long as possible, especially if it’s draining too fast.
What are some signs of over or underwatering? Brown leaf edges! Leaf drooping!
Learn more about this in our article on dying hydrangeas.
Coneflowers can survive temperatures ranging from -10 to -20°F in zone 5. They are perennials that can grow from about 2 to 5 feet. Their dark green pointed oval leaves are located below the plant. Coneflower blossoms are disk-like and cone-shaped.
Lighting conditions that are full sun (6–8 hours/day) to part shade are good for coneflowers.
They like evenly moist and well-drained soils, but they can tolerate both drought and heat once they’re already well-established.
In other words, they only need moderate watering at least once a week.
The center of coneflower blooms can attract butterflies, hummingbirds, and bees—all of which can help pollinate other plants in your garden!
When choosing which plants to add to a garden in zone 5, one must take their environmental needs into account. Since it can get pretty chilly in this region, it’s best to pick plants that grow well even in low temperatures—which can get into the negatives.
I kept this in mind while creating this list, so go ahead and plant them all or pick out your own favorites!
The table below summarizes the growing conditions needed for all 8 plants compatible with zones 5a and 5b.
|Common Name||Is This Perennial?||Water Requirement||Light Requirement||Blooming Season|
|Sedum||Yes||Moderate||Full sun to partial shade||Early Summer to Late Fall|
|Hosta||Yes||Moderate||Partial shade to shady||Spring to Early Autumn|
|Catmint||Yes||Low||Full sun||Late Spring to Early Summer|
|Bee Balm||Yes||Moderate||Full sun||Early Summer to Late Summer|
|Russian Sage||Yes||Moderate||Full sun||Late Spring to Autumn|
|Yarrow||Yes||Low||Full sun||Early Spring to Late Fall|
|Hydrangea||Yes||High||Full, partial shade, shady||Spring, Summer, and Early Fall|
|Coneflower||Yes||Moderate||Full sun to partial shade||Summer to Autumn|
The key difference between zones 5a and 5b is their average minimum temperature. For zone 5a it is -15°F to -20°F, while for zone 5b it is -10°F to -15°F. Also, the average first frost date in Zone 5 is observed from October 13 to 21, whereas the last frost date is from April 7 to 30.
When considering the plants to be grown in your specific zone, you should highly consider the frost date! This is because knowing the frost date will let you prepare. You can find out your frost date on this website.
Most plants that thrive in zone 5 are perennials, allowing them to continue growing from year to year. They are not that sensitive to frost!
But when you want to grow annuals, like vegetables, you must highly consider frost dates. For instance, if the frost date in your place is expected to be on April 30, you must plant your seeds earlier, so that they can grow before your frost date.
So to put it simply, select crops that can survive cold temperatures if you live in zone 5. Then, if you really want to grow veggies and herbs, which are annuals, you can consider indoor and greenhouse gardening—where you can control growing conditions.
Explore more in our article on seed germination and growing temperature of 63 plants.
The US states that are included in Zone 5 are:
- New Hampshire
- New Mexico
- New York
- South Dakota
- West Virginia
Please note, however, that although these states are classified under zone 5, there are instances where a single state can have areas classified under different zones.
Maine, for instance, covers areas under zones 3b, 4a, 4b, 5a, 5b, and 6a, with an average minimum temperature that ranges from -35°F to -5°F.
What are other plants that can grow well in zone 5 with minimal damage?
Asters, beets, chives, coral bells, coreopsis, and geranium are plants that can withstand zone 5 conditions with minimal damage such as frost injury and physical damage. These plants can also survive the cold temperatures found in zone 5.
What type of gardening is best for zone 5?
Since Zone 5 has a shorter growing season, indoor and greenhouse gardening is highly recommended. Although some plants have already acclimatized to zone 5 environmental conditions, growing indoors and inside greenhouses is still best for beginners, to assure good quality of the harvest.
Is rainfall essential in zone 5 classifications?
Rainfall is not a factor to consider in Zone 5. Rather, the average minimum temperature and frost dates are more essential for zone classifications. This is also because rainfall varies due to microclimate conditions, as well as macroclimate issues like climate change.
Zones 5a and 5b are divided based on their minimum average temperature. The lowest temperatures in zone 5a can go down to -15–-20°F, while zone 5b has an average minimum temperature of -10 to -15°F.
The best plants to grow in zone 5 conditions are perennials that can handle cold temperatures because they can live for several years. Such cold-tolerant perennials include sedum, hosta, catmint, bee balm, Russian sage, yarrow, hydrangea, and coneflower.
- “Yard and Garden: Effect of Extreme Cold on Trees and Shrubs” by Jauron, R. and Klein, W. in Iowa State University
- “Oregon Stonecrop” by Brooks, L. in University of Washington
- “Growing Hostas” by Westerfield, B. in University of Georgia
- “Nepeta (Catmint, Catnip)” by North Carolina State University
- “Growing Bee Balm in the Home Garden” by Jauron R. in Iowa State University
- “Russian sage, Perovskia atriplicifolia” by Mahr, S. in University of Wisconsin
- “Yarrow” by Lamborn, A.R. in University of Florida
- “General care for hydrangeas” by VanHoose, K. in Oregon State University
- “Echinacea” by Davenport, M. in Clemson University